1. Field of the Invention
The present invention relates to a LED (light emitting diode) lamp, and more particularly to a LED lamp having a LED unit and a plurality of heat sinks surrounding the LED unit for efficiently dissipating the heat generated by the LED unit.
2. Description of the Prior Art
Presently, projection lamps have a considerable market share among all of commercially available lamps. Especially, when various power-saving electronic lamps are used to replace traditional fluorescent lamps, the projection lamps still play an important role due to the fact that the projection lamps further providing a particular illuminating effect. For example, when decorating various house environments, exhibition places, showrooms, or restaurants, the projection lamps are inevitably used to create a mood for focusing on exhibited trade articles or decorations. Because the projection lamps have the considerable market share, various specifications of the projection lamps have been standardized. However, traditional projection lamps are generally halide projection lamps with a specification of 110 Volt, which results in increasing power consumption and generation of heat, so that the life span thereof is shortened relatively (only about several months). With the trend of higher and higher power rate, the traditional halide projection lamps are uneconomical and may cause an environmental issue; while the generated heat easily causes accidents such as cable fires.
To solve the foregoing problems, related manufacturers further developed projection lamps having LEDs (light emitting diodes) as a power-saving light source, so as to replace the traditional halide projection lamps. Referring now to FIG. 1, a schematic view of a traditional LED projection lamp is illustrated. The traditional LED projection lamp designated by numeral 1 comprises an outer casing 11, a voltage conversion unit 12, and a LED unit 13. The LED unit 13 and the voltage conversion unit 12 are mounted in the outer casing 11. The voltage conversion unit 12 is used to convert an AC power of 110V into a DC power applied to the LED unit 13, so that the LED unit 13 can illuminate for a projection purpose.
However, although the traditional LED projection lamp 1 provides a power-saving advantage relative to the traditional halide projection lamp, the traditional LED projection lamp 1 still has the foregoing problem of heat dissipation. In other words, the LED unit 13 must have a predetermined illumination in order to provide an effect of focusing on a spot target. Although the illumination of the LED unit 13 is continuously increasing with the advance of lamp technology, the heat-dissipation problem of the LED unit 13 is more and more serious. Especially, in comparison with the traditional halide projection lamp, the LED unit 13 only has a lower heat-resistant property. Once an operation temperature is greater than a predetermined heat-resistant temperature of the LED unit 13, the illumination of the LED unit 13 will be gradually decreased, so that the LED unit 13 can no longer provide the predetermined illumination and the life span thereof will be shortened.
Even though the traditional LED projection lamp 1 has the heat-dissipation problem, the traditional LED projection lamp 1 is still not provided with any heat-dissipation structure for dissipating heat. The heat generated by the LED unit 13 can only be dissipated to the atmosphere by the outer casing 11 made of metal, so that the traditional LED projection lamp 1 only provides a relatively lower heat-dissipation efficiency. Hence, the traditional LED projection lamp 1 can only use the LED unit 13 with a maximum power specification up to 1 Watt due to the heat-dissipation problem, so that the total illumination of the traditional LED projection lamp 1 is limited and the traditional LED projection lamp 1 cannot be used to completely replace the traditional halide projection lamp. As a result, the traditional halide projection lamp with the higher power consumption and the more heat generation still has a considerable market share, which leads to unnecessary waste of the limited energy resources in the world.
It is therefore tried by the inventor to develop a LED lamp to solve the problems existing in the traditional LED projection lamp as described above.